Fire alarm for telephones



Dec. 29, 1931. B. G. HOLMES FIRE ALARM RoR TELEPHONES 2 Sheets-Sheet Filed Jan. 22, 1931 y E 7 mw 9U r 7 Eff. d ,W w

Dec. 29, 1931. B. G. HOLMES 1,838,144

FIRE ALARM FOR TELEPHONES Filed Jan. 22, 1931 2 sheets-sheet 2 /6 FIG? 4. /fs 22 2a E .55 J5 J6 a /8 o 68 2", /s 25 "9 /9 j .35 a la C@ 37 ff C12. 2 \/a 72 D 30 i /75 v mg In ven tor.' 76 Il l Bernard CZen JYoZmes 77 By @Mba-fm ltvrmeg/ ject is to Patented Dec. 29, 1931 PATENT OFFICE BERNARD GLEN HOLMESQ F PHILADELPHIA, PENNSYLVANIA.

FIRE ALARM FOR TELEPHONES y.Application led January 22, 1931. Serial No. 510,399.

My invention relates to improvements in 'a fire alarm for telephones and particularly to a fire alarm adapted for use in connection with telephone systems, which are now in general use.

The object of my invention 1s to provide a irclalarm embodied in the telephonereceiving and transmitting instrument, and arranged for giving a signal at the telephone exchange when a fire occurs where thetelephone instrument is located; a further obconst'ruct the fire alarm in such a manner that it can be actuated only upon the occurrence of a fire and which cannot be operated accidentally, or by a person tampering with t-he fire alarm; a further object is to embody a fusible link in the hook of the telephone upon which the receiveris supported and arrange the hook so that one-half of the latter will fall off and allow the receiver to drop when the fusible link is melted by a tire occurring adjacent to the telephone instrument; a further object is to provide electrical contact, or switch plates which are normally separated when the telephone hook is operated in the usual manner, and which contact plates will be connected only when the two portions of the telephone hook are separated by the melting of the fusible link,

\ thus insuring that the fire alarm will not be given by the removal, or accidental falling olf, l

ofthe telephone receiver from the hook; a further object is to provide an electrical circuit including the contact plates which are closed to complete said circuit when the fusible link is melted, and include within said circuit a signaling device such as a buzzer which will give to the operator at the telephone eX- change a distinctive signal, which will be known as a fire alarm signal. These together with various other novel features of construction and arrangement of the parts, which will be more fully hereinafter described and claimed, constitute my invention.

Referring to the accompanying drawings Fig. 1 is a vertical central sectional view of a telephone instrument embodying my invention; Fig. 2 is a partial sectional view similar to Fig. 1, showing-the same after one hook member has been removed and the parts in al ing the telephone circuit or circuits in the position to close the regular telephone circuit and also close the fire alarm circuit; Fig. 3 is a vertical sectional view as on line 3 3, Fig.

1; Fig. 4 is a horizontal sectional view as on line 4-4,.Fig. 1; Fig. 5 is a perspective view 55 of one-half of the telephone hook detached; Fig. 6 is a perspective view of the other half of the telephone hook detached; and Fig. 7 is a diagrammatic view showing the alarm circuit energized by a battery, independently of 60 the telephone circuit.

Referring to the accompanying drawings in which like reference characters .refer to like parts 1() represents a telephone instrument of the type now in general use, comprising a G base 12, on which is secured the tubular body portion 13, the head 16 on whichis pivotally mounted the telephone transmitter 17 indicated in dot and dash lines. Upon the head 16 is secured a base-plate 18 by screws 19 which base-plate 18 is secured by a screw 2O to the base 12 in the usual manner.

The base-plate 18 forms a bearing 22 at its upper end for the pivot shaft 23 on which is pivotally mounted the arm 25 for carrying the receiver 26 indicated in dot and dash lines. The arm 25 is provided with the usual form of boss 28 which strikes the base-plate 18 when the arm is depressed by the weight of the receiver, as shown in'Fig. 1. In which position a button 29', of insulating material, which is secured upon the hook, engages a spring' 30 and movesthe latter out of engagement with contact plates 31 and 32 for openusual manner.

When the receiver is removed from the arm the spring 30 pushes against the button, raising the arm to the position shown in Fig. 2, and causing the contact plates to engage with each other and complete the various circuits for the operation of the telephone when the receiver is removed from the supporting arm. The contact plates 30, 31 and 32 are mounted upon the base-plate 18 in the usual manner. Binding screws 34 and 35 are secured .upon the base-plate, and have connected therewith the conductors 36 and 37 of a circuit which is energized from a source of power located at the telephone exchange, which circuit is utilized in carry-ing "out the present invention. The above delconsisting of two portions or members forming supporting members for supporting the telephone receiver 26 in the usual manner. The arm 25 forms one of the supporting members, and a detachable member 40 forms the other one of the supporting members. Said members are provided with hook portions 41 and 42 respectively. Said members also have vertical facing surfaces 43 and 44 which are secured together by a fusible connection 45 positioned along a central vertical plane, as shown in Fig.'4. One end portion 48 of the arm 25 is enlarged and forms a bearing 49 in which the pivot shaft 23 is mounted. The enlarged end portion 48 is recessed, as shown in Figs. 4 and 5, for the reception of the end portion 50 of the mem ber 40. The supporting members 25 and 40 are secured together by means of the fusible connection 45 consisting of readily fusible solder, whereby the weight of the telephone receiver will cause the member 40 to become detached from the other portion when the connection 45 is melted by an unusual increase in the temperature in the room where the telephone instrument is located due to the occurrence of a fire.

The arm o1' member 25 is provided with a tongue 52 formed integrally therewith which occupies a slot 53 formed in the member 40. Said tongue 52 forms a key which is provided for strengthening the supporting members forming the hook to withstand the strains to which the receiver arm is subjected when in use. However the tongue 52 does not prevent a lateral movement of the member 40 relatively to the arm or member 25 when the fusible .connection 45 is melted. Thus it will be seen that the member 40 will drop olf the member 25 when the fusible connection 45 is melted due to the weight of the receiver, thereby allowing the receiver to fall and the arm or member 25 to move upwardly into the position shown in Fig. 2, as it would when the telephone receiver is lifted from the arm in the usual manner, for the purpose of closing the telephone circuits with the eX- change.

The enlarged portion 48 of the armor member 25 is provided with an aperture 55 which is loosely occupied by a rod 56 formed of insulating material. One end of the rod 56 abuts against the detachable member 40, as shown in Figs. 1 and 4. Th-e opposite end of the rod is engaged by a spring switch plate 60 which is of L-shape formation at its upper end and provided with an enlarged portion at its lower end through which screws 62 and 63 are passed for securing the same to the `base-plate 18, from which the plate 60 is electrically insulated in-the usual manner. The screw 63 forms means for attaching an electrical conductor 65 in electrical contact with the spring plate 60. Said conductor 65 is connected with theconductor 37 of the telephone circuit. The enlarged portion 48 of the member 25 is also provided with a switch contact plate 68 which is insulated from said portion 48 in the usual manner. The plate 68 is provided with a binding screw 6) for the attachment of a conductor 7() forming part of an electric circuit, which is closed when the spring switch plate 60 engages the fixed plate 68. The rod 56 is of sufficient length to hold the spring plate 60 out of contact with the contact plate 68 when the two members 25 and 4() are secured together by the fusible connection 45 to form a vsupporting member for the receiver. When the fusible connection 45 is melted the member 40 drops olf the member 25, and the rod 56 will be free to move by the action of the spring switch plate 60, so that the latter makes contact with the xed plate 68, thus closing the circuit. The spring switch plate 60 is located at one side of the base-plate 18 relatively to the regular spring contact plates 30, 31 and 32 forming part of the telephone instrument, as shown in Fig. 3. Said plate 60 is of sufficient length to permit the receiver arm or hook to move up and dov'n during the usual operation of the telephone without the spring switch plate 60 engaging the fixed plate 68. Thus the circuit controlled by the plates 60 and 68 will be open as long as the two members 25 and 40 are secured together by the fusible connection 45.

The telephone instrument is provided with a buzzer 72 located in the base 12, which latter may be provided with a bracket 73 on which the buzzer is secured, as shown in Fig. l. One terminal of the buzzer is connected by the conductor 70 with the liXed switch plate 68 on the arm 25, and the other terminal of the buzzer is connected by means of a conductor 75 with the binding screw 34 upon the base-plate 18, which binding screw is also connected by means of the conductor 36 with the main telephone circuit having a source of supply at the telephone exchange. The spring switch contact plate 60 is connected through the binding screw 63 by means of the conductor 65 which is connected with a binding screw 35 upon the baseplate 18 to which is connected the conductor 37 forming part of the regular telephone circuit.

The buzzer 72, the switch plates 60 and 68, andthe conductors 65, 70 and 75 form a second circuit which may be connected in any suitable manner with the regular circuit forming part of the telephone equipment, so that said second circuit will be connected with a Source of electric supply suitable for operatarm orho6ldue to the melting of the fusible connection between the two portions of the rece1ver supporting arm.

The alarm circuit may be connected with a source of supply forming part of the tele- ,phone circuit, as above describedor it may include a battery 75, as shown in Fig. which may be located in any suitable position and connected by means of conductors 76 and 77 with the buzzer 72 and the switch'plate 60.`

When the switch plate 60is moved into contact with the fixed plate 68, by the melting of the fusible member 45, and the falling off of one portion of the receiver arm, the circuit including the buzzer will be energized by the battery 75.

The operation of my invention is as follows:

The switch contact'plates 60 and 68 and the buzzer 7 2 are arranged so that the telephone instrument can be operated in the usual manner without completing the second, or alarm circuit including the buzzer, and the receiver may be lifted, and remain off the hook or arm for an indefinite time without the alarm circuit being completed. Should a fire occurin the room where the telephone instrument is located, the increasing of the temperature to a given degree will melt the fusible connection 45 between the two members of the receiver supporting arm, so that one portion of the arm will fall and allow the receiver to fall. rlhe rod 56 may then be moved by the action of the spring switch plate 60, thus allowing the latter to move into electrical contact with the fixed contact plate 68 and complete the alarm, or second circuit inc-ludin g the buzzer. When the receiver falls from the arm the latter will automatically move into a position for closing the regular telephone circuits, thus energizing said second or alarm circuit. The vibration of the buzzer will c-ause Idistinctive sound vibrations to be set up in the instrument and the transmitter, which vibrations in the latter are carried through the regular telephone circuit including the transmitter to the telephone exchange.

The buzzer will produce a sound which is distinctive from the other sounds being conveyed to the telephone exchange from the telephone instrument, thus providing a distinctive signal which may be known as a fire alarm signal.

My invention provides a iire alarm which willv be operated automatically through the telephonel system and provides vmeans for giving an alarm when a fire occurs in a dwelling, or building, when there is no one present to otherwise give the alarm.

I claim 1. A telephone including a base, a receiver, separable supporting members operatively mounted upon the base for supporting the receiver, and a fusible connection betweenl said supporting members.

2. A telephone instrument yincluding a base, a receiver and an electrical circuit, separable supporting members operatively mounted upon the base for supporting thereceiver, a fusible connection between said members, and a signal device actuated when the fusible connection is melted.

3. A telephone instrument including a base, a receiver, an arm pivotally mounted upon the base, a hook member upon said arm, a second hook member, a fusible connection between said second hook member and the arm arranged for positioning the hook members for supporting the receiver, an electric telephone circuit automatically closed by the removal of the receiver from the arm, a' second electric circuit, and a.

switch in said second circuit actuated by the hook members when operated by the melting of the fusible connection.

4. A telephone instrument including a base, a receiver, an arm pivotally mounted upon the base, a hook member upon said arm, a second hook member, a fusible connection between said second hook member and the arm arranged for positioning the hook members for supporting the receiver, an electric telephone circuit automatically closed when the receiver is removed from the arm, a switch plate upon said arm, a spring switch plate upon said base arranged for normally engaging said switch plate, a second circuit including said switch plates, a part movably mounted upon said arm positioned between thespring switch plate and said second hook member arranged for separating the switch plates when said second hook member is positioned upon the arm by said fusible oonnection, and a signal device in said second circuit actuated when the fusible connection is melted by the closing of said second circuit.

5. A telephone instrument including a base, a receiver, an arm pivotally mounted upon the base, a hook member upon said arm, a second hook member, a fusible connection between said second hook member and the arm arranged for positioning the hook members for supporting the receiver and arranged for dropping the receiver from the hook members when the latter are separated by the melting of the fusible connection, an electric telephone circuit automatically closed by the tioned upon the arm by said fusible connection, a slgnal device included in-said-second cicuit actuated when the fusible connection is melted, and means for mounting said lsignal device upon said base for producing a distinctive signal.

IIx-testimony whereof I aflix my signature.

BERNARD GLEN HOLMES. 

